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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Reference
Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Qualifier:
according to guideline
Guideline:
EU Method C.3 (Algal Inhibition test)
Qualifier:
according to guideline
Guideline:
ISO 8692 (Water Quality - Fresh Water Algal Growth Inhibition Test with Scenedesmus subspicatus and Selenastrum capricornutum)
GLP compliance:
yes (incl. QA statement)
Analytical monitoring:
yes
Details on sampling:
- concentrations - all
- Sampling method: 100 uL taken and added to appropriate vials to maintain conconcentation
- Sample storage conditions before analysis: stored at 2-10C and shipped at the end of the test
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
The test material was purged through test media for different periods of time at a rate of 20 ml/min. The gas flow was assessed using a soap-bubble flow meter. To incease the availablity of CO2 for the alga when inclubated in a closed vessel, extra NaHCO3 was added resultin in a concentration of 100 mg/L.
Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
TEST ORGANISM
- Strain: NIVA CHL-1
- Source: in house laboratory culture

ACCLIMATION
- Culturing media and conditions (same as test or not): same as test
- Any deformed or abnormal cells observed: no
Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
72 h
Nominal and measured concentrations:
limit test; average 170 mg/L (measured prior to adding alga); average exposure concentration at 72 hours = 75 mg/L (maximum average concentrations 114 mg/L)
Details on test conditions:
TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): closed
- Material, size, headspace, fill volume: all glass and airtight closed with a screw cap holding a septum
- Aeration: no
- Initial cells density: 10000 cells/ml
- Control end cells density: 580000 cells/mL
- No. of vessels per concentration (replicates):6
- No. of vessels per control (replicates):6
- No. of vessels per vehicle control (replicates):1


GROWTH MEDIUM
- Standard medium used: yes

OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Light intensity and quality: 71-82 uE.m(-2)s(-1)


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: counting chamber and spectrophotometer
Reference substance (positive control):
yes
Remarks:
potassium dichromate
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
75 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
75 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
biomass
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
> 75 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
> 75 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
biomass
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
biomass
Details on results:
- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): no
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values:no
- Effect concentrations exceeding solubility of substance in test medium
Results with reference substance (positive control):
- Results with reference substance valid? yes
- EC50: 72 hr cell growth inhibition 0.78 mg/L, 72 hr growth rate reduction 1.6 mg/L

Due to the closed system used, the pH varied more than 1.5 between the the start (~ 8.5) and end of the the study (~ 10.2) for both control and treated replicates. However, the exponential algal growth was not affected so this deviation did not adversely affect the study outcome. The cell density increased by a factor of ~ 60 within 3 days and the temperature remained in the ranged prescribed by the deadline.

Validity criteria fulfilled:
yes
Remarks:
temperature and cell growth within limits, pH increased more than 1.5 due to closed system used. However, exponential growth rate was not affected and this deviation did not affect the validity of the study.
Conclusions:
Under the conditions of the present study,with the fresh water green algae Selenastrum capricornutum, the NOEC of the test substance for growth of this fresh water algae species is > 75 mg/L. Since no effect was recorded at this level and at the maxium average exposure of 114 mg/L, in one of the treated solutions, it can be safely concluded that the EC50 of the test substance for algal growth is > 100 mg/L based on both the area under the growth curve and growth rate. The test substance can be classified as not harmful to fresh water alga.

Description of key information

HFO-1234yf has low toxicity to algae.

Key value for chemical safety assessment

Additional information

HFO-1234yf has low toxicity to alga with a 72 hr EC50 greater than 100 mg/l. Under the conditions of the present study with the fresh water green algae Selenastrum capriconutum, the NOEC of HFO-1234yf for growth of this fresh water algae species is > 75 mg/l. Since no growth inhibition was recorded at this level and at the maximum average exposure of 114 mg/l, in one of the treated solutions, it can be safely concluded that the EC50 of HFO-1234yf for algal growth is > 100 mg/l based on both the area under the growth curve and growth rate. HFO-1234yf can be classified as not harmful to fresh water alga.